Wedge press for continuous dehydration of a web of fibrous material, such as fiberboard, especially

ABSTRACT

Device for continuous dehydration of a web of fibrous material including two pressure plates pervious to water and mutually disposed so as to form a wedge-shaped gap therebetween, the wedge angle of the gap and the mutual spacing of the pressure plates being adjustable, and a water-permeable belt looped around the pressure plates respectively, one of the pressure plates having a portion projecting beyond the other pressure plate at the narrow end of the wedge-shaped gap, suction chamber means located at least at the projecting portion and at a region of the one pressure plate immediately preceding the projecting portion in direction of feed of a web of fibrous material through the wedgeshaped gap from the wide to the narrow end thereof, the other pressure plate being formed with perforations.

United States Patent Csordas et al.

WEDGE PRESS FOR CONTINUOUS DEHYDRATION OF A WEB OF FIBROUS MATERIAL, SUCH AS FIBERBOARD, ESPECIALLY Inventors: Elemer Csordas; Karl Gaugenmaier,

both of Heidenheim, Brenz;

Gerhard Kotitschke, Steinheim, all

Primary Examiner-Peter Feldman of Germany Attorney, Agent, or FzrmHerbert L. Lerner [73] Assignee: J. M. Voith GmbH, Heidenheim,

Germany 57 ABSTRACT [22] Filed: May 7, 1974 Device for continuous dehydration of a web of fibrous material including two pressure plates pervious to [21] Appl' 467672 water and mutually disposed so as to form a wedgeshaped gap therebetween, the wedge angle of the gap [30] Foreign Application Priority Data and the mutual spacing of the pressure plates being May 10, 1973 Germany 2323519 adjustable, and a Water-Permeable looped around the pressure plates respectively, one of the pressure 521 US. Cl. 100/90; 100/118; 100/154; Plates having a Portion Projecting beyond the other 162/301; 1 2 3 3 pressure plate at the narrow end of the wedge-shaped [51] 1m, Cu 3303 9/00; 1321 1/44; 211: 1/00 gap, suction chamber means located at least at the [58 Field of Search 100 90, 118, 119, 120, projecting Portion and at a region of the one Pressure 5ll54; 162/363, 364, 358, 351, 313, plate immediately preceding the projecting portion in 203 301 direction of feed of a web of fibrous material through the wedge-shaped gap from the wide to the narrow [56] References Cit d end thereof, the other pressure plate being formed UNlTED STATES PATENTS Perfmamns- 1,599,253 9/1926 Skolnik 162/203 X 2 Claims, 1 Drawing Figure I v a a 0/ II 2! 79\ A\ m a E- L i I 9/ 8/ Zl- -l US. Patent Dec. 30, 1975 3,929,665

WEDGE PRESS FOR CONTINUOUS DEHYDRATION OF A WEB OF FIBROUS MATERIAL, SUCH AS F IBERBOARD, ESPECIALLY The invention relates to a wedge press for the continuous dehydration of a web of fibrous material, such as fiberboard, especially, and to such a wedge press which, more particularly, has two pressure plates that are pervious to water and that form therebetween a wedge-shaped gap, that the wedge angle and mutual spacing between the pressure plates being adjustable, each of the pressure plates having a belt (screen, felt) looped therearound.

In known devices of this general type, such as are disclosed in German Published Prosecuted application DAS 1561643, the pressure increases so much during compression of the web that danger. of crushing and lump formation arises. Furthermore, due to this high pressure, heavy wear occurs at the pressure plates and the web belts. i

It is accordingly an object of the invention to provide a wedge press for continuous dehydration of a web of fibrous material, such as fiberboard, especially, which avoids the foregoing disadvantages of the heretofore known devices of this general type and which dehydrates webs of fibrous material in an economical manner.

With the foregoing and other objects in view, there is provided, in accordance with the invention, a device for continuous dehydration of a web of fibrous material comprising two pressure, plates pervious to water'and mutually disposed so as to form a wedge-shaped gap therebetween, the wedge angle of the gap and the mutual spacing of the pressure plates being adjustable, and a water-permeable belt looped around the pressure plates respectively beyond the other pressure plate at the narrow end of the wedge-shaped gap, suction chamber means located at least at the projecting portion and at a region of the one pressure plate immediately preceding the projecting portion in direction of feed of a web of fibrous material through the wedgeshaped gap from the wide to the narrow end thereof, the other pressure plate being formed with perforations.

Thorough dehydration of the web is thereby achieved without it being necessary for the pressure in the wedge gap to become very high. The pressure in the wedge gap is made up of the mechanical pressure per se that is applied from the outside, and the hydraulic pressure building up inside. In the wedge press according to the invention, however, this hydraulic pressure is very low, because the suction chambers alreadydraw off water from the web of fibrous material during the compression process. The pressed-out water can be'discharged through the perforations in the other pressure plate or,

with suitably high under-pressure, air can be sucked into the web of fibrous material. The suction chamber extending beyond the wedge gap furthermoreprevents re-wettingof the pressure-relieved web.

In accordance with another feature of the invention the one pressure plate extending beyond the wedgeshaped gap is formed with perforations at a region thereof located at the wide end of the wedge-shaped gap through which the web of fibrous material is fed into the gap.

Very advantageous dehydration of the web over the entire area of the press is thereby assured.

Other features which are considered as characteristics for the invention are set forth in the appended claims.

Although the invention is illustrated and described herein as embodied in a wedge press for continuous dehydration of a web of fibrous material, such as fiberboard, especially, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when .read in connection with the single feature, of the drawing which is a diagrammatic view, partly in section, and partly broken away, of the wedge press for continuous dehydration of a web of fibrous material, constructed in accordance with the invention.

Referring now to the drawing, there is shown therein a wedge press having two screens 1 and 2 defining therebetween a wedge-shaped gap wherein there is received a web of fibrous material 3 to be dehydrated, which is fed into the device on an elongated screen 4. The lower screen 1 of the two screens, as viewed in the figure, travels over a stationary screen table 5, which is provided. with several suctio'n chambers 6, 7 and8 that are disposed one behind the other in travel direction of the screen.' Thesesuction chambers are divided into two groups, one of which being connected to a suction line 10 through asuction space 9 and the other to a suction line 12 through a suction space 11. Opposite the screen table 5, another screen table 13, along which the upper screen 2 runs, is located. The distance and the angle of this screen table 13 with respect to the screen table 5 are adjustable. The rear end face of the screen table 13 in the direction of travel of the screen engages a stop 14, on and alongwhich it can slide in vertical direction. Instead of the ,stop 14, a tie bar 15 articulatingly connected to the screen table 13 may be provided, as shown by the dash-dot lines. Two vertically extending adjusting spindles lb and 17 are also articulatingly connected to the screen table 13, the, adjusting spindle 17 serving to set the aperture or opening width of the wedge gap formed by the two screens 1 and 2, while the adjusting spindle 16 sets the maximum compression of the web of fibrous material 3. A guide roller l8.for the screen 2 also is disposed at the screen table 13 in such a manner as to ensure that the reversing or deflection angle of the screen 2 at the location at which it runs onto the screen table 13 does not change if the latter is moved. The surface of the screen table 13 supporting the screen 2 is formed with perforations 19, behond which chambers 20 are disposed for receiving and discharging water that has been pressed through the screen 2. The ,last of the chambers 20 in direction of travel of the screen is located sub stantially above the last suction chamber 7, of the second group of suction chambers of the lower screen table 5, the screen table 13 ending directly behind the last chamber 20 therein. The last suction chamber 8 of the lower screen table 5 consequently is free and applies suction to the web of fibrous material when the pressure diminishes, thereby preventing re-wetting of the web.

Instead of the suction line 10, only a discharge line for the squeezed-out water might be provided, because, in this section A of the wedge press, the hydraulic pressure has not yet become very great. In the sections B and C of the wedge press, the chambers 7 and 8, however, are provided with a suction line, so that air can be sucked into the web of fibrous material, through the perforations l9 and the chambers 20 or after the end of the upper pressure plate, whereby the water flows out of the web of fibrous material.

We claim:

1. Device for continuous dehydration of a previously formed web of fibrous material, such as fiberboard, containing moisture, comprising two pressure plates pervious to water and mutually disposed so as to form a wedge-shaped gap therebetween, the wedge angle of said gap and the mutual spacing of said pressure plates being adjustable, and a water-permeable belt looped around said pressure plates, respectively, one of said pressure plates having a terminating portion projecting beyond the other pressure plate at the narrow end of said wedge-shaped gap, suction chamber means located at least at said terminating projecting portion so as to apply suction to the web as the pressure exerted by the pressure plates on the web terminates for preventing rewetting of the web and additional suction means at a region of said one pressure plate immediately preceding said projecting portion in direction of feed of a web of fibrous material through said wedgeshaped gap from the wide to the narrow end thereof, said other pressure plate being formed with perforations.

2. Device according to claim 1 wherein said one pressure plate extending beyond said wedge-shaped gap is formed with perforations at a region thereof located at the wide end of said wedge-shaped gap through which the web of fibrous material is fed into said gap. 

1. Device for continuous dehydration of a previously formed web of fibrous material, such as fiberboard, containing moisture, comprising two pressure plates pervious to water and mutually disposed so as to form a wedge-shaped gap therebetween, the wedge angle of said gap and the mutual spacing of said pressure plates being adjustable, and a water-permeable belt looped around said pressure plates, respectively, one of said pressure plates having a terminating portion projecting beyond the other pressure plate at the narrow end of said wedge-shaped gap, suction chamber means located at least at said terminating projecting portion so as to apply suction to the web as the pressure exerted by the pressure plates on the web terminates for preventing rewetting of the web and additional suction means at a region of said one pressure plate immediately preceding said projecting portion in direction of feed of a web of fibrous material through said wedge-shaped gap from the wide to the narrow end thereof, said other pressure plate being formed with perforations.
 2. Device according to claim 1 wherein said one pressure plate extending beyond said wedge-shaped gap is formed with perforations at a region thereof located at the wide end of said wedge-shaped gap through which the web of fibrous material is fed into said gap. 